This invention relates to an arm structure for an injecting molding machine, particularly to one not needing to take off a connecting rod in removing an arm structure from a receiving disc and a movable mold base.
A conventional injecting molding machine with an arm structure shown in FIG. 7, includes a table 10, an injecting structure 20 fixed on one side of the table 10, and a movable mold base 40 and a receiving disc 50 combined with through holes at four corners by means of connecting rods 30 on the other side of the table 10. The movable mold base 40 is connected to a piston rod of an oil pressure cylinder 501 connected with the arm structure and the receiving disc 50. The oil pressure cylinder 501 operates to move the movable mold base 40 to open and close the mold.
The arm structure has arms 601 consisting of pivotal plates 6011 respectively having first ends fitted between two position plates 502, as shown in FIG. 8, wherein the receiving disc 50 is shown as an example of pivotally connected to the am structure. The movable mold base 40 is also pivotally connected to the arm structure in the same way. It is not described and not shown in Figures. Then a long pivot 503 passes through pivot holes 504 of the receiving disc 50 (or the movable mold base 40) and pivot holes (not shown in Figures) of each pivotal plate 6011. Thus, the two ends of the arms 601 of the arm structure are respectively and pivotally connected to the receiving disc 50 and the movable mold base 40.
However, this kind of arm structure has been used for years and it is not very convenient when the arm structure is to be taken off or to be assembled together as the connecting rods have to be first disassembled from the movable mold base or from the receiving disc and then the pivot 503 can be taken off to let the arm structure removed. This complicated pivotal connection involves much work and time in assembling and disassembling the arm structure with and from the movable mold base and the receiving disc.
In addition, each position plate 502 has the through hole vertical to form 90xc2x0 against the receiving disc 50 and the movable mold base 40 so in boring the through holes of all position plates 502 or the same holes in the movable mold base, the receiving disc 50 or the movable mold base 40 has to be fixed on the surface of a boring machine and have to be aligned accurately for boring the through (pivot) holes of the position plates. Then the receiving disc 50 or the movable mold base 40 is turned for 90xc2x0 and then aligned accurately for boring the through holes of the receiving disc or the movable mold base (or those in the position plates), as shown in FIG. 9.
As can be understood from what is described, in boring the pivot holes or the through holes of the receiving disc 50 and the movable mold base 40, it requires two times of alignment and correct boring with little errors resulting in much time and work.
This invention has been devised to offer an arm structure for an injecting molding machine, wherein a receiving disc and a movable mold base respectively have plural parallel position plates, which respectively have an outer end concave surface bored with a threaded hole, and an arm structure consists of two pairs of two armsxe2x80x94a first and a second onexe2x80x94positioned at two sides of the receiving disc and the movable mold base.
The first and the second arm respectively have plural parallel pivotal plates, and an outer end of each parallel pivotal plate fits in a gap defined by every two position plates of the receiving disc and the movable mold base. Then a tubular pivot respectively passes through the outer ends of the plural parallel pivotal plates and also fits in the concave end surfaces of the parallel position plates. Further, each tubular pivot has plural through holes corresponding to the threaded holes of the outer end concave surfaces of the parallel position plates of the receiving disc and the movable mold base for bolts to pass through the through holes and screw with the threaded holes for assembling the arm structure with the receiving disc and the movable mold base. Thus, the arm structure is pivotally connected between and to the receiving disc and the movable mold base. Therefore, the arm structure can be assembled with or disassembled from the receiving disc and the movable mold base only by taking off the bolts passing through each tubular pivot and screwing off the threaded holes.